21 research outputs found
Restoring the prestige of the engineering education through a fourth engineering wave in the development of the fundamental scientific knowledge of economy
There is no doubt that in the EU and the USA, engineering education has completely lost its previous prestige. The finest youths have shifted away from aspiring to become engineers towards aspiring to become professional economists and businessmen. It has been forgotten that the enterprises for machines, which are best understood by engineers, are the backbone of every national economy. Furthermore, the lack of human capital capable of managing their economy efficiently, as well as supporting their internal activities, will lead not only to us observing a shift of the finest youths steering away from engineering but also a shift away from a sustainable economic future. This paper presents a new approach that will bring back the previous and welldeserved prestige of the all-important engineering education, a prestige connected to the names of Henry Towne, Frederick Taylor, William Deming, and all the engineers responsible for the three engineering waves in the development of the fundamental scientific knowledge of economy. However, we find ourselves on the brink of a fourth engineering wave in the development of the fundamental scientific knowledge of economy. A wave connected to the Bulgarian-based Institute for Systemic Economic Engineering, which has successfully developed а systemic universal model of the enterprise for machines, a model widely thought to be impossible to develop, but if developed successfully, would bring economic changes equal to the combined magnitude of the economic changes brought by all the previous engineering waves and would form a new type of professional defined by the term “systemic economic engineers”
Radial-velocity jitter of stars as a function of observational timescale and stellar age
Stars show various amounts of radial velocity (RV) jitter due to varying
stellar activity levels. The typical amount of RV jitter as a function of
stellar age and observational timescale has not yet been systematically
quantified, although it is often larger than the instrumental precision of
modern high-resolution spectrographs used for Doppler planet detection and
characterization. We aim to empirically determine the intrinsic stellar RV
variation for mostly G and K dwarf stars on different timescales and for
different stellar ages independently of stellar models. We also focus on young
stars ( 30 Myr), where the RV variation is known to be large. We use
archival FEROS and HARPS RV data of stars which were observed at least 30 times
spread over at least two years. We then apply the pooled variance (PV)
technique to these data sets to identify the periods and amplitudes of
underlying, quasiperiodic signals. We show that the PV is a powerful tool to
identify quasiperiodic signals in highly irregularly sampled data sets. We
derive activity-lag functions for 20 putative single stars, where lag is the
timescale on which the stellar jitter is measured. Since the ages of all stars
are known, we also use this to formulate an activity--age--lag relation which
can be used to predict the expected RV jitter of a star given its age and the
timescale to be probed. The maximum RV jitter on timescales of decades
decreases from over 500 m/s for 5 Myr-old stars to 2.3 m/s for stars with ages
of around 5 Gyr. The decrease in RV jitter when considering a timescale of only
1 d instead of 1 yr is smaller by roughly a factor of 4 for 5 Myr old stars,
and a factor of 1.5 for stars with an age of 5 Gyr. The rate at which the RV
jitter increases with lag strongly depends on stellar age and ranges from a few
days for a few 10 Myr old stars to presumably decades for stars with an age of
a few gigayears.Comment: 15 pages, 7 Figures; Changelog v2: Updated link to CDS for table E.1;
rearranged Fig. 2 to match journal layou
The Minimal Wall
Sustainability, and more specifically embodied carbon emissions, have become one of the most prominent challenges for the facade industry. Discussions around the topic focus on the global warming potential of materials and their recycled content, whilst efficiency and innovation in design as a way to reduce embodied emissions have not yet received the same level of attention. This article proposes evolved structural design and detailing methods for glass-metal facades that minimise the amount of materials needed to meet their serviceability and structural integrity requirements. The discussion focuses on structural sealant glazing and the composite behaviour of glass and frame to resist out of plane loads. The study promotes capitalizing on the inherent contribution of the adhesive connection towards the flexural stiffness of façades and proposes ways of enhancing it for further structural optimization. The impact of the adhesive connection is assessed through an experimental program consisting of extensive four-point bending tests of representative beam samples and corresponding numerical studies. The article provides an interpretation of the interim results and discusses the potential of the proposed solutions to contribute towards a holistic approach to reduce the global warming potential of building envelopes. Finally, directions for future research needed for practical applications of the proposals are presented and discussed
Universality in Uncertainty Relations for a Quantum Particle
A general theory of preparational uncertainty relations for a quantum particle in one spatial dimension is developed. We derive conditions which determine whether a given smooth function of the particle's variances and its covariance is bounded from below. Whenever a global minimum exists, an uncertainty relation has been obtained. The squeezed number states of a harmonic oscillator are found to be universal: no other pure or mixed states will saturate any such relation. Geometrically, we identify a convex uncertainty region in the space of second moments which is bounded by the inequality derived by Robertson and Schrödinger. Our approach provides a unified perspective on existing uncertainty relations for a single continuous variable, and it leads to new inequalities for second moments which can be checked experimentally
New HARPS and FEROS observations of GJ1046
In this paper we present new precise Doppler data of GJ1046 taken between
November 2005 and July 2018 with the HARPS and the FEROS high-resolution
spectographs. In addition, we provide a new stellar mass estimate of GJ1046 and
we update the orbital parameters of the GJ1046 system. These new data and
analysis could be used together with the GAIA epoch astrometry, when available,
for braking the degeneracy and revealing the true mass of the GJ1046
system.Comment: 2 pages, 1 figure, 1 table with RV data (available only in the
Astro-PH version of the paper), Accepted by RNAA
Design of primers and optimization of PCR conditions for the detection of alternatively spliced isoforms of mouse ChAT mRNA
Acetylcholine plays an important role as a neurotransmitter in the central and peripheral nervous systems. Its biosynthesis is catalyzed by choline acetyltransferase (ChAT). In mice, the ChAT gene has three 5′-noncoding (R, N, and M) and 14 coding exons, from which seven mRNA isoforms (M, N1, N2, R1, R2, R3, and R4) are transcribed. They differ in the 5′-noncoding ends and encode the same protein (common ChAT). An additional isoform that lacks coding exons from 5 to 8 encodes a smaller protein (peripheral ChAT). This research aimed to design and check the specificity of primers targeting R3, N1, N2, M, peripheral ChAT, and common ChAT isoforms. The optimal PCR conditions and specificity of the primers were tested in a series of PCR reactions. Specially designed DNA fragments or plasmids containing isoform-specific nucleotide sequences were used as templates. The appropriate annealing temperature, which yields sufficient specificity for each tested primer pair, was as follows: R3 – 60 °C; N1 – 63 °C; N2 – 65 °C; M – 65 °C; peripheral ChAT – 65 °C and common ChAT – 63 °C
A syntactic approach to foundational proof-carrying code
Proof-Carrying Code (PCC) is a general framework for verifying the safety properties of machine-language programs. PCC proofs are usually written in a logic extended with language-specific typing rules. In Foundational Proof-Carrying Code (FPCC), on the other hand, proofs are constructed and verified using strictly the foundations of mathematical logic, with no type-specific axioms. FPCC is more flexible and secure because it is not tied to any particular type system and it has a smaller trusted base. Foundational proofs, however, are much harder to construct. Previous efforts on FPCC all required building sophisticated semantic models for types. In this paper, we present a syntactic approach to FPCC that avoids the difficulties of previous work. Under our new scheme, the foundational proof for a typed machine program simply consists of the typing derivation plus the formalized syntactic soundness proof for the underlying type system. We give a translation from a typed assembly language into FPCC and demonstrate the advantages of our new system via an implementation in the Coq proof assistant. 1
Risk factors for gut colonization with vancomycin-resistant enterococci among Bulgarian critically ill patients
Abstract Vancomycin-resistant enterococci (VRЕ) are recognized as important hospital pathogens which have become common in patients admitted to the intensive care units (ICUs). The purpose of this study was to evaluate the incidence of and the risk factors for colonization with VRE among ICU patients. A total of 91 patients who had duration of hospitalization more than 48 h and without infection caused by VRE or/and other microorganisms in the ICU at University Hospital, Pleven were screened for colonization with VRE. The following data were collected: demographic characteristics, clinical information and antimicrobials use. The statistical analysis was performed using SPSS version 27.0. Colonization with VRE was established in 22 patients and one was carrying two enterococcal species. A total of 23 VRE were isolated. The univariate analysis showed that the postoperative critical cares (p < 0.001), cardiovascular diseases (p = 0.009) and the presence of an endotracheal tube (p = 0.003) were risk factors for colonization with VRE. Also, the postoperative critical cares (p = 0.021) and cardiovascular diseases (p = 0.018) were confirmed as independent risk factor for VRE acquisition by multivariate analysis. The prevalence of VRE colonization among the ICU patients was relatively high (24.2%). Risk factors for acquisition of intestinal VRE were the postoperative cares, cardiovascular diseases and the presence of an endotracheal tube
Long-lived exciton coherence in mixed-halide perovskite crystals
Compositional engineering of the optical properties of hybrid
organic-inorganic lead halide perovskites is one of the cornerstones for the
realization of efficient solar cells and tailored light-emitting devices. We
study the effect of compositional disorder on coherent exciton dynamics in a
mixed FACsPbIBr perovskite crystal using photon
echo spectroscopy. We reveal that the homogeneous linewidth of excitons can be
as narrow as 16eV at a temperature of 1.5K. The corresponding exciton
coherence time of ps is exceptionally long being attributed to the
localization of excitons due to variation of composition at the scale of ten to
hundreds of nanometers. From spectral and temperature dependences of the two-
and three-pulse photon echo decay we conclude that for low-energy excitons,
pure decoherence associated with elastic scattering on phonons is comparable
with the exciton lifetime, while for excitons with higher energies, inelastic
scattering to lower energy states via phonon emission dominates